GMAT Quantitative Reasoning Practice Test 8

Statement (1) implies that the annual interest is 8.5%. it is not sufficient by itself since we do not have the time period of the return.
Statement (2) implies that 12 years have passed until Merline paid the loan but we do not have the interest rate.
During the 12 years, we can calculate the interest every year until we reach 12 years. Both statements together are sufficient.
A simple interest can be calculated using the following formula:
Principle (money loaned or invested) × rate (percent) × time = interest paid